package com.lwx.thread.product;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

class BoundedBuffer {
    final Lock lock = new ReentrantLock();
    final Condition notFull = lock.newCondition();
    final Condition notEmpty = lock.newCondition();

    final Object[] items = new Object[10];
    int putptr, takeptr, count;

    public void put(Object x) throws InterruptedException {
        lock.lock();
        try {
            while (count == items.length)
                notFull.await();
            items[putptr] = x;
            if (++putptr == items.length) putptr = 0;
            ++count;
            notEmpty.signal();
        } finally {
            lock.unlock();
        }
    }

    public Object take() throws InterruptedException {
        lock.lock();
        try {
            while (count == 0)
                notEmpty.await();
            Object x = items[takeptr];
            if (++takeptr == items.length) takeptr = 0;
            --count;
            notFull.signal();
            return x;
        } finally {
            lock.unlock();
        }
    }
    
    public static void main(String[] args) {
        final BoundedBuffer boundedBuffer = new BoundedBuffer();
        for(int i = 0; i < 100; i++){
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        boundedBuffer.put(1);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }).start();
        }
        
        for(int i = 0; i < 8; i++){
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        System.out.println(boundedBuffer.take());
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }
}
